Abnormal Intrapartum Fetal Heart Rate Research Articles

182 C/section as an appropriate intervention for abnormal intrapartum fetal heart rate tracings

182 C/section as an appropriate intervention for abnormal intrapartum fetal heart rate tracings

PROPHYLACTIC AMNIOINFUSION FOR INTRAPARTUM OLIGOHYDRAMNIOS

In Brief Objective: To evaluate the effectiveness of intrapartum prophylactic amnioinfusion in pregnancies complicated by oligohydramnios. Data Sources: Randomized controlled trials of prophylactic amnioinfusion in women with oligohydramnios were identified using computerized databases, index reviews, and references cited in original studies and review articles. Methods of Study Selection: We evaluated, abstracted data from, and analyzed randomized studies of prophylactic intrapartum amnioinfusion in women with oligohydramnios. In every study the group allocation was based exclusively on presence of oligohydramnios. Only published studies with clearly documented outcome data were included. The quality of each trial was evaluated for methodology, inclusion and exclusion criteria, adequacy of randomization, amnioinfusion protocols, definition of outcomes, and statistical analyses. The trials were evaluated concerning cesarean deliveries for fetal heart rate (FHR) abnormalities, overall cesarean rates, acidemia at birth, intrapartum fetal heart rate abnormalities, Apgar scores under 7 at 5 minutes, and postpartum endometritis. Tabulation, Integration, and Results: Thirty-five studies were identified, of which 14 met the inclusion criteria for this systematic review. They included 1533 patients, 793 in the amnioinfusion group, and 740 controls. Odds ratios (OR) with their 95% confidence intervals (CI) for each outcome were calculated. We calculated an estimate of the OR and risk difference for dichotomous outcomes using random and fixed-effects models. A test of homogeneity was done across studies. Women with oligohydramnios who received intrapartum amnioinfusion had lower incidence of cesarean for FHR abnormalities (OR 0.23; 95% CI 0.15, 0.35). Intrapartum amnioinfusion also was associated with lower overall rates of cesarean deliveries (OR 0.52; 95% CI 0.40, 0.68), acidemia at birth (OR 0.40; 95% CI 0.30, 0.55), FHR abnormalities during labor (OR 0.24; 95% CI 0.17, 0.34), and Apgar scores under 7 at 5 minutes (OR 0.52; 95% CI 0.29, 0.91). Postpartum endometritis rates were similar among the study groups. Conclusion: In the presence of oligohydramnios, prophylactic intrapartum amnioinfusion significantly improves neonatal outcome and lessens the rate of cesarean delivery, without increasing the rate of postpartum endometritis. Intrapartum amnioinfusion in oligohydramnios improves neonatal outcomes and reduces cesarean deliveries without increasing the frequency of postpartum endometritis.

Intrapartum tocolysis has no effect on fetal lactate concentration

Objective: To assess the fetal metabolic effects of intrapartum maternal tocolysis with terbutaline in the presence of fetal heart rate abnormalities, with a special emphasis on lactate concentration, in view of its potential use as a marker of fetal condition. Design: Descriptive study. Setting: Two labour wards, National University Hospital, Singapore, and Östersund Hospital, Sweden. Methods: Eight parturients with abnormal intrapartum fetal heart rate recordings were given bolus i.v. injection of 0.25 mg terbutaline and monitored both before and 20 minutes after treatment. Results: Maternal venous glucose increased from 5.0 (0.9) (mean (SD)) to 5.6 (1.2) mmol/l ( p=0.002) and fetal scalp blood glucose rose from 4.1 (1.8) to 4.7 (1.4) mmol/l ( p=0.009) 20 minutes after the injection. No significant change was found in maternal or fetal lactate concentrations. Conclusion: Terbutaline tocolysis for “intrauterine resuscitation” does not affect fetal lactate concentration 20 minutes after treatment.

Cesarean delivery for intrapartum fetal heart rate abnormalities: Incorporating survey data into clinical judgment

To identify the descriptive clinical practice of maternal-fetal medicine specialists when faced with severe intrapartum fetal heart rate (FHR) abnormalities (as determined by continuous electronic fetal monitoring). All regular members of the Society of Perinatal Obstetricians (maternal-fetal medicine specialists) were sent a survey questionnaire on the topic of cesarean delivery for intrapartum FHR abnormalities. The time from observation of FHR abnormalities to making the decision to proceed to cesarean delivery was the main outcome measure. Time was allowed for intrauterine resuscitative maneuvers to alleviate the abnormal pattern. Legislative definitions of consensus and strong consensus were applied to the data. Analysis of covariance was performed to determine the effect of physician demographic factors on the times reported. Four hundred thirty-one of 704 (61.2%) questionnaires were returned. Consensus was identified for deciding on cesarean delivery (after intrauterine resuscitation) 1) after 30 minutes for cases of repetitive late and severe variable decelerations, 2) after 10 minutes in cases of fetal bradycardia, and 3) in all scenarios with decreased beat-to-beat variability of the FHR. Consensus was identified for deciding on cesarean delivery in five of eight intrapartum FHR pattern abnormalities. The descriptive clinical practice of maternal-fetal medicine specialists demonstrated in this study should be considered in prudential clinical judgment.

Perinatal diagnostic evaluation of velamentous umbilical cord insertion: Clinical, doppler, and ultrasonic findings

To evaluate the association between velamentous cord insertion and adverse pregnancy outcome in singleton pregnancies, and to assess the diagnostic usefulness of nonstress testing (NST) and Doppler ultrasound in this condition. We retrospectively reviewed 12,750 consecutive singleton, chromosomally normal pregnancies from July 1989 through December 1993 at the University Hospital of Kuopio, Finland. Of these, 216 were complicated by velamentous umbilical cord insertion, whereas the remaining 12,534 were normal controls. Using multiple regression analysis, we evaluated the risks by noting adverse infant outcomes: low birth weight (LBW), small for gestational age (SGA), preterm delivery, fetal death, admission to a specific infant care unit, low Apgar scores, neonatal acidemia, and abnormal intrapartum fetal heart rate (FHR) patterns. At prenatal visits, NST and Doppler ultrasound examinations were carried out as a routine part of obstetric care. Even after we controlled for confounding factors, velamentous umbilical cord insertion was associated with higher risk of LBW (odds ratio [OR] 2.32), SGA (OR 1.54), preterm delivery (OR 2.12), low Apgar scores at 1 and 5 minutes (ORs 1.76 and 2.47, respectively), and abnormal intrapartum FHR pattern (OR 1.59). Only 5% of the patients with abnormal insertion showed pathologic NST results at prenatal visits. Ultrasonographic examination was carried out on 80 patients with velamentous umbilical cord insertion as a routine part of obstetric care, and in only one case was direct visualization of the abnormal insertion successful. After we excluded pregnancies with preeclampsia, abnormal umbilical artery Doppler velocimetry was found in none of the cases examined (n = 48). There were substantial differences in pregnancy outcome measures between the subjects with velamentous umbilical cord insertion and controls. Current antepartum methods of tracing uteroplacental problems are not effective in the prenatal detection of abnormal insertion. Therefore, in future studies, the use of other diagnostic tools, such as color Doppler imaging of cord insertion, should be evaluated in high-risk pregnancies followed-up because of fetal growth restriction.

Diagnostische und klinische Wertigkeit der Dopplersonographie in der Geburtshilfe

The diagnostic value (efficiency) of Doppler ultrasound in obstetrics is assessed by studying the association or correlation between Doppler measurement parameters and pregnancy outcome parameters, without influencing the clinical management. The clinical value (efficacy) is however assessed by studying the ability to improve the outcome of pregnancy if Doppler ultrasound is used in obstetrical management for the purpose of possible intervention. The accepted method for assessment of the diagnostic value is the observational study, and the best method for the assessment of the clinical value is the randomised controlled management study (clinical trial). Observational studies concerning the diagnostic value have been widely reported in the literature. According to these studies significant relationships between abnormal Doppler findings and the following obstetrical problems were found: intrauterine growth retardation, preterm delivery, acidosis determined by fetal blood sampling, abnormal intrapartum fetal heart rate, neonatal depression and acidosis, and admission to neonatal intensive care unit. However from these studies it cannot be concluded that pregnancy outcome will be improved by using this information clinically. This problem can only be properly addressed by appropriate clinical management studies. The majority of the published randomised controlled trials showed beneficial effect from Doppler ultrasound application in high-risk pregnancy management. These effects included a significant decrease in the duration of antenatal and neonatal hospital stay, the rate of labour induction, and the rate of emergency Caesarean section. At the same time there was no difference in the gestational age at delivery or in the total Caesarean section rate. None of these trials alone was large enough to demonstrate a statistically significant reduction in perinatal mortality. However cumulative meta-analysis allows pooling to evaluate the results from separate but similar studies. The results from such an analysis showed that in high-risk pregnancies managed with Doppler there is a significant decrease of 50 per cent in perinatal mortality and in stillbirths of anatomically normal fetuses. It is important to note that there was no increase in neonatal or maternal morbidity associated with the use of Doppler ultrasound, and that the reduction in perinatal mortality was not the result of a delay in timing fetal death.

Computerized analysis of fetal heart rate variation in postterm pregnancy: Prediction of intrapartum fetal distress and fetal acidosis

Our purpose was to evaluate whether computerized analysis of fetal heart rate variation may improve fetal surveillance in postterm pregnancy. Three hundred thirty-seven pregnant women who were delivered after 41 weeks' gestation and who had 610 antenatal tests were included in this study. Fetal tests included a nonstress test with a computerized analysis of the fetal heart rate, Doppler examination of the umbilical artery, and a biophysical profile, performed every 2 to 4 days. Induction of labor was performed when the fetal heart rate variation was reduced (< 30 msec), when fetal heart rate decelerations appeared, or when the amniotic fluid index was < or = 5. The results of the fetal surveillance tests were compared with the results of the intrapartum fetal heart rate monitoring and with the metabolic status of the babies at delivery. Sensitivity and specificity of the various tests in predicting intrapartum fetal distress and acidosis at delivery were described by means of the receiver-operator characteristic curve. Ten of 12 fetuses with reduced fetal heart rate variation had a trial of labor. Nine of these 10 fetuses had fetal distress during labor. Seven of the 12 fetuses with reduced fetal heart rate variation were acidotic at delivery (umbilical artery pH < 7.2). Overall, there were 10 acidotic fetuses at delivery in the study group. Only two of them had an umbilical systolic/diastolic ratio > 95th percentile, three had an amniotic fluid index < or = 5, and five had fetal heart rate decelerations before labor. Fetuses who demonstrated an abnormal intrapartum fetal heart rate tracing or who were acidotic at delivery had a significantly higher rate of reduced fetal heart rate variation or decelerations before labor. The largest area under the receiver-operator curve curve for predicting fetal acidosis at delivery or fetal distress during labor was achieved by means of computerized analysis of fetal heart rate variation. A computerized numeric analysis of fetal heart rate variation may improve fetal surveillance in postterm pregnancy.

Umbilical cord blood erythroblast count as an index of intrauterine hypoxia.

The relation of umbilical cord blood arterial pH, Apgar score, leucocyte count, and erythroblast count at delivery with the diagnosis of fetal distress in labour was studied prospectively in three groups of singleton pregnancies delivering at term vaginally (55 infants), by elective caesarean section (39 infants), or by emergency caesarean section for abnormal intrapartum fetal heart rate patterns (55 infants). In the emergency caesarean section group the umbilical cord blood arterial pH was significantly lower and the leucocyte and erythroblast counts were higher than in the elective caesarean section group. Comparison of the emergency caesarean section and spontaneous vaginal delivery groups showed significant differences for pH and erythroblast count, but not for leucocyte count. In the spontaneous vaginal delivery group erythroblastosis was associated with umbilical cord blood pH, whereas leucocytosis was associated with the length of labour. The five minute Apgar score was > or = 7 in all infants. This study suggests that leucocytosis is a non-specific response of the fetus to labour, whereas erythroblastosis reflects fetal tissue hypoxia.

Intrahepatic cholestasis of pregnancy: A retrospective case-control study of perinatal outcome

OBJECTIVES: Intrahepatic cholestasis of pregnancy has been related to a high frequency of abnormal intrapartum fetal heart rate, amniotic fluid meconium, prematurity, and perinatal mortality. To determine whether these adverse perinatal outcomes could be improved with active intervention, we evaluated our results. STUDY DESIGN: We report a retrospective case-control study of 320 consecutive patients with intrahepatic cholestasis of pregnancy management with antepartum testing and active intervention over a 2-year period. RESULTS: Our results indicate a higher incidence of meconium staining in amniotic fluid at delivery (25% vs 16%, p < 0.05) and spontaneous preterm delivery (12.1% vs 3.9%, p < 0.05), without an increase in the frequency of abnormal intrapartum fetal heart rate (12% vs 11%, not significant), 5-minute Apgar score <7 (2.0% vs 1.0%, not significant), or perinatal mortality (18/1000 vs 13/1000, not significant). CONCLUSION: Antenatal testing and timed intervention of patients with intrahepatic cholestasis of pregnancy is associated with a reduction of the previously reported adverse perinatal outcomes. (AM J OBSTET GYNECOL 1994;170:890-5.)

Umbilical artery doppler velocimetry compared with fetal heart rate monitoring as a labor admission test

A total of 155 patients admitted in early labor to the delivery unit of the University of Hong Kong were recruited into a study comparing the value of umbilical artery Doppler velocimetry and fetal heart rate (FHR) monitoring in early labor as an admission test. FHR monitoring for 30 min was recorded on admission, and umbilical A B ratio was simultaneously performed. The FHR tracing was scored according to the Lyons score by a third independent observer after delivery. Outcome variables studied included small for gestational age (SGA), intrapartum FHR abnormalities, operative deliveries for fetal distress, umbilical cord pH, Apgar scores, admission into the special care baby unit, and a combination of the variables. It was found that at cut-off values of Lyons score < 7 and umbilical A B ratio > 2.6 at term, about 19% of cases were abnormal for either tests, with only a few cases of overlap. Umbilical A B ratio was found to be significantly correlated with SGA. The sensitivity and positive predictive values were, however, low. Both tests were relatively poor predictors for most of the outcome variables studied. Interestingly, FHR monitoring did not seem to have any advantage over Doppler velocimetry as a labor admission test. Further larger scale studies to evaluate their usefulness in medium and low risk populations are indicated.

The use of fetal echocardiography for predicting intrapartum fetal heart rate patterns in the post-term pregnancy.

One of the shortcomings of antepartum testing in the post-term pregnancy is that it does not identify the majority of fetuses who develop abnormal intrapartum fetal heart rate changes. The purpose of this study was to determine whether antenatal cardiovascular evaluation could aid in the identification of post-term fetuses at risk for intrapartum heart rate abnormalities. Seventy-five patients with a gestational age greater than 41 weeks underwent a non-stress test, amniotic fluid index and real-time assessment of the heart for the presence or absence of a pericardial effusion. M-mode measurements of the right ventricular inner dimension (RVID), left ventricular inner dimension (LVID), biventricular outer dimension (BVOD) and Doppler velocimetry of the umbilical artery (S/D) were performed. Group I (n = 32) had normal intrapartum heart rate tracings. Group II (n = 20) had abnormal intrapartum fetal heart rate tracings but did not undergo emergency delivery. Group III (n = 23) had abnormal intrapartum fetal heart rate tracings but underwent emergency delivery. When comparing Group I with Group II, the latter had significant differences for abnormal RVID, RVID/LVID ratio, and pericardial effusion. When comparing Groups I and III, there were significant differences for RVID, RVID/LVID ratio, pericardial effusion, BVOD, LVID and amniotic fluid index. Neither the non-stress test nor S/D predicted abnormal intrapartum fetal heart rate patterns. For prediction of abnormal intrapartum heart rate patterns, the sensitivities of the RVID (0.79), LVID (0.33), RVID/LVID ratio (0.72) and BVOD (0.63) were 1.7-4 times greater than the non-stress test (0.19) and the sensitivities of the RVID, RVID/LVID ratio and BVOD were 2 times greater than the amniotic fluid index (0.28). The positive (0.50-0.86) and negative (0.42-0.68) predictive values were similar for all groups. To predict emergency delivery associated with abnormal heart rate tracings, the sensitivities of the RVID (0.83), RVID/LVID ratio (0.70) and BVOD (0.65) were 2.5-3 times greater than the non-stress test (0.26) and 1.5 times greater than the amniotic fluid index (0.39). The positive (0.36-0.56) and negative (0.70-0.86) predictive values were similar. The presence of pericardial effusion had a higher sensitivity than the non-stress test and amniotic fluid index for predicting abnormal intrapartum heart rate patterns but not emergency delivery. Doppler velocimetry of the umbilical artery had a lower sensitivity than the non-stress test and amniotic fluid index for predicting intrapartum heart rate patterns as well as identifying the fetus needing emergency delivery. The results of this study would suggest that there is initially dilatation of the right ventricle which may be associated with abnormal intrapartum fetal heart rate patterns. However, when the left ventricle dilates, leading to cardiomegaly, there is a greater incidence of abnormal intrapartum fetal heart rate changes and associated emergency delivery. The amniotic fluid index appears to be a later finding for predicting abnormal intrapartum fetal heart rate changes.

Intrapartum assessment of fetal well-being: A comparison of fetal acoustic stimulation with acid-base determinations

Many authorities advocate the use of fetal blood sampling as the final arbiter of abnormal intrapartum fetal heart rate patterns. Alternatively, the presence of an acceleratory fetal heart rate response to scalp stimulation during fetal scalp blood sampling led to the observation that, if present, the likelihood of acidosis was remote. Consequently a prospective intrapartum analysis of evoked accelerations and fetal acid-base status was undertaken. Patients who, on the basis of abnormal fetal heart rate patterns, were judged candidates for acid-base assessment underwent transabdominal acoustic stimulation. The presence or absence of an acceleration was then determined. Sixty-four patients with abnormal intrapartum fetal heart rate patterns underwent intrapartum acoustic stimulation. Thirty fetuses were reactive and all had a pH of greater than or equal to 7.25. Of the 34 fetuses who were nonreactive, 18 were acidotic. This preliminary observation suggests that acoustic stimulation may be a reasonable clinical alternative to fetal blood sampling when a reactive pattern is observed. In the nonreactive fetuses additional evaluation would appear warranted.

Early seizures indicate quality of perinatal care.

An analysis of antepartum, intrapartum, and postpartum variables was performed in a retrospective controlled study of 34 normally formed term infants who had perinatal asphyxia and subsequently displayed generalised seizures within 48 hours of birth. The aim was to identify any association, firstly between these variables and seizures, and secondly between these variables and subsequent morbidity and mortality among the seizure group. Maternal age greater than 35 years, duration of labour, meconium stained liquor, abnormal intrapartum fetal heart rate trace, and operative delivery were associated with seizures. A low Apgar score at five minutes, and intermittent positive pressure ventilation at birth of longer than 10 minutes were associated with subsequent morbidity and mortality. A striking relation between poor intrauterine growth and either death or handicap in the asphyxia group emphasised the value of growth measurements as a predictor of outcome. The overall incidence of seizures was 1.6 per 1000 term deliveries. There was a significant correlation between the seizure incidence and the intrapartum mortality rate. The incidence of seizures secondary to asphyxia in term infants, occurring less than 48 hours after delivery, may be a valuable index of the quality of perinatal care.

The fetal biophysical profile and its predictive value.

Six fetal biophysical variables--the nonstress test, fetal movements, fetal breathing movements, fetal tone, amniotic fluid volume, and placental grading (biophysical profile)--were assessed in 150 high-risk pregnancies during a 30-minute observation period. The predictive value of the nonstress test alone, biophysical scoring, and contraction stress test alone in the identification of the healthy fetus as well as the fetus in jeopardy are discussed. The relationships between individual variables and combinations of variables to the outcome of pregnancy, as reflected by abnormal intrapartum fetal heart rate patterns, meconium during labor, fetal distress, and perinatal mortality rate were determined. The biophysical profile of all hypoxic fetuses was analyzed. These data suggest that the biophysical profile is more accurate in the identification of the hypoxic fetus than any other single method; therefore, a new protocol including the biophysical profile for antepartum fetal evaluation is presented.